1. Field
The present disclosure generally relates to vacuum bag equipment and supplies used to fabricate composite parts, and deals more particularly with an expandable surface breather that conforms to complex contoured surfaces of part layup.
2. Background
During the fabrication of composite parts, surface breathers may be positioned over a surface of a part layup that is subsequently processed under vacuum beneath a sealed vacuum bag. The breather provides a generally uniform breathing path on the surface of the layup that allows air and volatiles to escape from the layup during compaction and curing processing cycles. Removing air and volatiles is desirable in order to reduce part porosity and improve part performance. Breathers typically comprise polyester or nylon, nonwoven materials in various weights and thicknesses that are cut to size for a particular application.
Covering part layups with breather materials is difficult where the part contains complex surface contours formed by part features. Larger pieces of breather material placed over these features may gap over, also known as bridging, rather than conform to the surface features. In order to avoid these gaps, breather materials are cut into multiple individual strips of varying widths which are carefully placed on and around complex contoured surface features in order to substantially completely cover the part layup without bridging. The use of multiple breather strips to cover a part layup is time consuming and may result in material waste, particularly where the part layup is very large and has complex contours.
Accordingly, there is a need for a one-piece breather that may be quickly and easily draped over the entire surface area of a part layup and which conforms to complex part contours during vacuum bag processing. There is also a need for a method of fabricating composite parts that reduces labor costs and material waste, and which avoids bridging of breather materials.